Manually driven bathtub lift

ABSTRACT

A manually driven bathtub lift for assisting persons of limited strength or mobility into or out of a typical bathtub without the high costs associated with pneumatic, hydraulic or electric lift devices. A seat is attached to a wheeled trolley arranged for movement up an inclined track mounted on a base frame. A chain is disposed about a drive sprocket and a set of guide pulleys and attached to opposite ends of the trolley. The set of pulleys includes an idler that is biased to retain tension in the chain. The drive sprocket is driven by the rotation of a driver wheel supported on the same shaft as the sprocket. Rotation of the sprocket drives the chain which in turn moves the trolley and attached seat. The driver wheel has handles circumferentially spaced around it and is of large enough size that it can be reached and operated from the seat. The lift is light to allow for easily installation and removal and does not require significant strength to operate.

The present invention relates to a mechanical bathtub lift seatapparatus for assisting persons of limited mobility, such as the elderlyor disabled, transfer into or out of a typical bathtub.

BACKGROUND

Persons having permanently limited mobility or strength to due to age ordisability may have difficulty performing certain typical daily tasks.Entry to or exit from a bathtub is an example of such a task, as itrequires transition between a standing position outside the tub and aseated position upon a very low surface within the tub, includingclimbing over the side wall.

As a result, there are a number of existing products aimed at assistinga user enter and exit the tub by easing the aforementioned transition.These products include inflatable chairs positioned within a bathtub forlowering and raising the user to and from the bottom of the tub in aconstantly seated position. Other seat assemblies can be positionedwithin a tub for the same purpose, but are driven by water actuatedcylinders or electric motors. Some of these assemblies feature rotatingseats so that the user can initially sit with his/her legs outside thetub and then rotate their legs over the tub wall before being lowered,eliminating the step of unassisted entry to the tub altogether. Otherdevices, typically driven by electric motors, are capable of actuallytransferring the user from a seated position entirely outside the wallsof the tub to a seated position within. One lowering system involves aband spanning from a wall-mounted dispenser on one side of a tub to thewall of the tub opposite the dispenser. An electric motor within thedispenser slowly dispenses more length of the band in order to lower auser seated on the band into the tub. Once bathing is completed, themotor is run in an opposite direction to retract the band into thedispenser, thereby lifting the user back up to the top of the tub.

The primary problem associated with the existing bathtub lift devices isthe high cost involved. The need for components such as air compressors,seals and adaptors for water driven devices, electric motors and controlsystems, coupled with possible installation costs, keeps many of theseproducts financially out of reach for many of those in need of theassistance that would be provided. Many elderly or disabled persons liveon limited income and cannot justify the high cost of the existingbathtub lift systems despite the comfort and safety levels they offer.As a result, there is a need for a bathtub lift apparatus that can beproduced and sold at a reasonable cost.

SUMMARY

According to one aspect of the present invention there is provided abathtub lift apparatus for assisting a person into and out of a bathtubcomprising:

a base frame for being received in the tub, the base frame including atrack supported on the frame having a lower end and an upper end;

a trolley supported for movement along the track;

a seat for supporting the person thereon, the seat being supported onthe trolley device for movement with the trolley between a lowerposition at the lower end of the track and an upper position at theupper end of the track;

a rotatable drive member supported for rotation on the frame;

an elongate driven member engaged about the drive member and connectedto the trolley for displacement of said trolley as the drive member isrotated; and

a driver device for rotating the drive member.

Preferably the base frame comprises two laterally spaced parallel walls,wherein the drive member and elongate driven member are located betweensaid walls.

Preferably the track comprises two laterally spaced track members, eachhaving an upper and lower surface defining an elongate channeltherebetween for receiving the trolley.

Each of the upper and lower surfaces of the track members may comprise arail.

Alternatively, the upper surface of each track member may comprise arail while the lower surface of each track member comprises the baseframe.

Preferably there is provided roller members supported on each side ofthe trolley supported for movement along the track.

Preferably the roller members are supported in pairs on axles mounted tothe trolley.

Preferably the track is non-linear between the upper and lower endsthereof.

The seat may be pivotally supported on the trolley for pivotal motionrelative thereto.

In this arrangement, preferably there is provided:

a pivotal mounting mechanism for pivotally supporting the seat on thetrolley for pivotal motion between the lower position where the seat isgenerally horizontal and the trolley is inclined along the track and alifting position where the seat and trolley are both inclined along thetrack and generally parallel to each other; and

an abutment member mounted on the seat that abuts with the trolley toprevent the seat from pivoting passed the lifting position where theseat and trolley are generally parallel.

Preferably the elongate driven member is flexible.

The elongate driven member may be endless.

Preferably the elongate driven member is guided by idler memberssupported on the base frame.

Preferably one of the idler members is floatingly supported on the baseframe and biased in order to maintain tension in the elongate drivenmember.

Preferably the idler members comprise pulleys.

Preferably the elongate driven member comprises a chain and the drivermember comprises a sprocket for engaging the chain.

Preferably the driver device comprises a rotational member having aseries of handles circumferentially spaced therearound.

In this arrangement, preferably the handles comprise openings in therotational member.

Alternatively, the driver device may comprise a hand crank mechanism forrotating the drive member.

Preferably the driver device is accessible by the person supported inthe seat.

Preferably there is provided a locking mechanism for selectivelypreventing motion of the seat relative to the base frame.

Preferably the locking mechanism is coupled between the driver deviceand the base frame.

Preferably the locking mechanism comprises:

an opening in the driver device;

a corresponding opening in the base frame;

a pin for passing through the opening in the driver device into theopening in the frame, thereby blocking motion of said driver device, andhence the driver member, elongate driven member, trolley and seat,relative to said frame.

Preferably the base frame and the driver device comprise aluminum.

The present invention can be made and sold at substantially lower coststhan existing bathtub lifts as a result of its simple mechanicalstructure. Assembly is simple and affordable, as the drive system notrequire any complex, costly or custom components and the base frame iseasy to fabricate. The apparatus is hand driven and therefore does notrequire the use of an external power source, such as an electric motoror air compressor and corresponding control mechanism. Furthermore, thesimplicity of the apparatus ensures that any maintenance will be minimaland affordable.

The driver device is reachable from the seat of the lift and thereforemay be used by a bather without outside assistance. The driver device isof substantial size such that the amount of torque needed to lift thebather supported on the seat can be achieved with relatively littleforce. As a result, the bather does not require a lot of strength to usethe apparatus and is therefore less likely to require assistance. Usinga material of relatively high strength to weight ratio such as aluminumto construct the frame and driver device, the weight of the apparatus iskept to a minimum so that the lift can be easily lowered into and liftedout of a typical bathtub. This is ideal for the cases where more thanone person uses the tub on a regular basis and the lift is not alwaysneeded. There is no need for professional installation, which helps keepdown the overall cost of the lift apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings, which illustrate an exemplary embodimentof the present invention:

FIG. 1 is a side elevational view of the bathtub lift with the seat inthe lowered position.

FIG. 2 is a side elevational view of the bathtub lift with the seat inthe raised position.

FIG. 3 is a rear elevational view of the bathtub lift with the seat inthe lowered position.

FIG. 4 is a rear elevational view of the bathtub lift with the seat inthe raised position.

FIG. 5 is a top plan view of the bathtub lift with the seat in thelowered position.

FIG. 6 is a top plan view of the bathtub lift with the seat in theraised position.

FIG. 7 is a cross sectional view of the bathtub lift with the seat inthe raised position as taken across line VII-VII of FIG. 6.

DETAILED DESCRIPTION

The following description outlines the details of a bathtub lift forassisting persons of limited mobility, such as the elderly or disabled,transfer into or out of a typical bathtub. One embodiment of the presentinvention is shown from the side in FIGS. 1 and 2. The bathtub liftapparatus 1 features a base frame 10 for supporting the apparatus withinthe bathtub (not shown), a seat 20 for supporting the bather and adriver device 40 for controlling motion of the seat 20. The liftfunctions in such a manner as to move the seat 20 between a lowerposition as seen in FIG. 1 and a raised or upper position as seen inFIG. 2. The seat 20 has a backrest portion 21 and a bottom portion 22connected by an angled portion 23. The user can sit upon the bottomportion 22 in the raised position from outside the tub, rotate his orher body in order to dispose each leg on an opposite side of theapparatus and then descend gradually to the lowered position within thetub. Once finished bathing, the user can then use the control device 40to ascend back to the raised position and then rotate his or her legsover the tub wall in order to exit the bathtub.

The movement of the seat is achieved through rolling motion of a trolley30 attached to the seat 20. The base frame 10 includes a pair of spacedapart parallel vertical walls 11 each having an upper edge 12 defininggenerally horizontal lower 17 and upper 18 portions and an inclinedportion 16. The walls 11 are connected and spaced apart at the end ofthe upper portion 16 by a horizontal base member 13 at the bottom of theframe 10 and vertical end wall 15 disposed above the base member asshown in FIGS. 3 and 4. A track assembly 50 is supported on each wall11. The track includes a rail 51 which is held above the base frame 10by rail supports 52 that extend generally perpendicular to the upperedge 12 of the walls 11. The rail 51 and supports 52 are connected bybolts 53 in order to form a channel 54 defined by a space between therail 51 and the upper edge 12 of the wall 11. This channel 54 definesthe path along which the trolley 30 can move. The trolley includeswheels 32 disposed on each side of the trolley body 31 for rollingmotion within the channel 54. The track extends along the inclined 16and upper 18 portions of the upper edge 12 so that the seat 12 attachedto the rear end of the trolley 30 can move between the lower positionabove lower portion 17 to the raised position above the inclined portion16. The inclined portion 16 is curved in order to provide a smoothtransition of the trolley 30 to and from the upper 18 and lower 17portions.

Components of the drive system for the trolley are disposed between thewalls 11 of the base frame 10 and are illustrated in FIG. 7. A chain 82is positioned around a drive sprocket 45 and guide pulleys 91, 94 and 96and attached to the trolley 30 at opposite ends. A first end of thechain 82 is attaches to the trolley 31 by means of attachment member 34bolted to the chain 82 and the trolley body 30 at an end opposite theseat 20. From this first end, the chain extends around the sprocket 45down to a floating idler pulley 91 which is mounted on a lever 92 forpivotal movement about an axis defined by a shaft 93 supported at eachend by a wall 11 of the base frame 10. This arrangement allows movementof the idler pulley 91 in order to retain tension in the chain 82 as thetrolley 30 moves along the track 50. The chain extends from the idler 91over a guide pulley 94 supported between the walls 11 by a shaft 95. Thechain further extends from the guide pulley 94 around a third pulley 96supported on a shaft 97 near the end of the lower portion 17 oppositethe inclined portion 16. This pulley 96 reverses the chain directionback toward the drive sprocket 45 for connection to a second trolleyattachment member 33 at an end of the trolley 30 nearest the seat 20.Similar to the first attachment member, the second attachment member 33is bolted to the chain 82 and the trolley body 31. With the seat 20 inthe lowered position as shown in FIG. 1, rotation of the sprocket 45 ina clockwise direction drives the chain 82 in a manner that pulls thetrolley 30 along the track 50 up the inclined portion 16 to the upperportion 18, moving the seat 20 toward the upper position shown in FIG.2. The shafts 95 and 97 that support the pulleys 94 and 96 at the lowerportion 17 further are connected to a wall 11 of the base frame 10 ateither so that they not only support the pulleys, but also keep thewalls spaced apart at that end of the apparatus.

The rotation of the drive sprocket 45 is achieved by means of thecontrol device 40. The control device 40 includes a drive wheel 49having a series of handles 41 formed by holes circumferentially spacedaround the wheel. As seen in FIGS. 3 and 4, the drive wheel is attachedto a rotatable member 46 by means of bolts 43. The rotatable member isfixed on the same shaft 45 as the drive sprocket 81. The shaft 45extends transversely through aligned holes in the vertical walls 11 ofthe base frame 10 near their upper edges 12 at the upper portion 18. Theshaft is free to rotate with respect to the frame 10, but lateralmovement along its axis is prevented by the combination of a pin 48 andblocking plate 47 as shown in FIGS. 3-6. The blocking plates 47 aresupported on the shaft 45 just outside each vertical wall 11 and thepins 48 pass through openings in the shaft just outside the plates.Lateral movement of the shaft 45 with respect to the frame 10 isprevented by the abutment of either pin 48 with the respective blockingplate 47. Rotation of the drive wheel 40 and attached rotatable member46 causes the sprocket 81 to turn and drive the chain 82, resulting inmotion of the trolley 30 and attached seat 20. The wheel 40 is ofsufficient size that the handles 41 are within reaching distance of theuser when supported on the seat 20 regardless of the position of thetrolley 30 along the track 50. The amount force needed to pull theseated user up the inclined portion 16 is kept reasonably small as therelatively large radius of the driver wheel 49 ensures a proportionallylarge resultant torque about the axis of the shaft 45.

The force of gravity on the user when seated in the raised positiontends to cause the trolley 30 and attached seat 20 to descend down theinclined portion 16 to the lowered position. As a result, a lockingmechanism is provided for selectively securing the trolley 30 in thetrack 50 at the upper portion 18 of the walls 11 of the base frame 10,thus locking the seat 20 in the raised position above the inclinedportion 16. A hole 42 in the driver wheel 49 is positioned in order toalign with a corresponding hole 14 in the wall 11 of the base frame 10on the same side of the lift apparatus 1 as the wheel 49 when the seat20 is in the raised position. A pin 70 is passed through the alignedholes 42 and 14 in order to prevent motion of the wheel 49 with respectto the base frame 10. Since the wheel 49 is attached to the rotatablemember 46 which is mounted on the same shaft 45 as the drive sprocket,rotation of any of these components is prevented by the pin 70. Thetrolley 30 and seat 20 cannot move with the pin 70 in place as the cogsof the stationary sprocket 81 prevent motion of the chain 82.

A pivoting mechanism 60 is provided between the trolley 30 and the seat20 to allow pivotal motion of the seat with respect to the trolley asthey move along the track 50. A pair of hinges 63 provides the pivotingaction between the seat 20 and trolley 30. Each hinge has flaps 61 and62 attached to the trolley body 31 and the seat 20 respectively. Asshown in FIG. 1, the hinge 63 allows the bottom portion 22 of the seat20 to take on a nearly horizontal orientation in the lowered position atthe lower portion 17 of the wall 11 even though the trolley 30 is at anangled orientation along the inclined portion 16. As the trolley 30 ispulled upward along the inclined portion 16 by the chain 82 the hingewill open further such that the bottom portion 22 of the seat 20 willtake on an the same orientation as the trolley 30, in other wordsparallel to the inclined portion 16. An abutment member 64 is attachedto the underside of the bottom portion 22 of the seat 20 in order toprevent the hinge 63 from opening more than 180 degrees. In the raisedposition shown in FIGS. 2 and 7, the hinge 63 opens under the weight ofthe seat 20 (and user, if seated thereupon) and moves the abutmentmember 64 into contact with the trolley body 31. This keeps the bottomportion 22 of the seat in a generally horizontal orientation in whichthe user can easily get on or off the seat 20 for entering or exitingthe tub respectively.

Due to the handles 41 circumferentially disposed about the drive wheel49 the lift is operable by either the bather or an assistant. The batheris lowered into the tub from the raised position shown in FIG. 2 byremoving the locking pin 70 from the aligned holes 42 and 14 in thedrive wheel 49 and wall 11 respectively. The weight of the bather on theseat will tend to move the seat 20 and attached trolley 30 down theinclined portion 16, pulling on the chain 82 and causing counterclockwise rotation of the sprocket 81 and the attached shaft 45. Sincethe driver wheel 49 is mounted on the same shaft 45 by means of therotational member 46, the counter clockwise rotation can be resisted bymeans of the handles 41, thereby controlling the speed of descent of thebather towards the lowered position shown in FIG. 1. In order to exitthe tub, the seat 20 is moved upward along the inclined portion 16 fromthe lowered position by rotating the driver wheel 49 clockwise by meansof the handles 41. Once the seat 20 has reached the raised position, theholes 41 and 14 of the locking mechanism will be realigned so that thelocking pin 70 can be inserted to lock the seat in the raised positionwhile the bather dismounts the lift apparatus.

The above description outlines a single embodiment of the presentinvention from which a number of alternate embodiments can be derived bythose who are skilled in the art. Alternate styles of frames, seats,trolleys, tracks, drive members, driven members and guide members can beassembled to achieve similar results. One alternate embodiment mayemploy a rope and winch for lifting and lowering the seat, in which casethe rope would only have to extend between the winch and the end of thetrolley nearest the upper portion eliminating the need for the guide andtension pulleys. Another alternate embodiment could use a notched beltand pulley combination instead of the chain and sprocket. Otherembodiments could feature a trolley arranged to move along a singletrack member or elongate handles extending outward from the drive wheeltransverse to the apparatus. The trolley and seat could also be combinedinto a single rigid component, eliminating the need for the pivotingmechanism. In this arrangement, the track would not extend to ahorizontal upper portion of the frame. The trolley would only move alongan inclined section of track and therefore would always be oriented atthe same angle with respect to the frame. Without the pivot mechanism,the seat would not move relative to the trolley but would remain fixedat an orientation similar to that of the lowered position of the seat inthe preferred embodiment, as shown in FIG. 1. As a result, the bottomportion of the seat would remain in a generally horizontal orientationwhen moving between the lowered and raised positions.

Since various modifications can be made in my invention as herein abovedescribed, and many apparently widely different embodiments of same madewithin the spirit and scope of the claims without department from suchspirit and scope, it is intended that all matter contained in theaccompanying specification shall be interpreted as illustrative only andnot in a limiting sense.

1. A bathtub lift apparatus for assisting a person into and out of abathtub comprising: a base frame for being received in the tub, the baseframe including a track supported on the frame having a lower end and anupper end; a trolley supported for movement along the track; a seat forsupporting the person thereon, the seat being supported on the trolleydevice for movement with the trolley between a lower position at thelower end of the track and an upper position at the upper end of thetrack; a rotatable drive member supported for rotation on the frame; anelongate driven member engaged about the drive member and connected tothe trolley for displacement of said trolley as the drive member isrotated; and a driver device for rotating the drive member.
 2. Theapparatus according to claim 1 wherein the base frame comprises twolaterally spaced parallel walls, wherein the drive member and elongatedriven member are located between said walls.
 3. The apparatus accordingto claim 1 wherein the track comprises two laterally spaced trackmembers, each having an upper and lower surface defining an elongatechannel therebetween for receiving the trolley.
 4. The apparatusaccording to claim 3 wherein each of the upper and lower surfaces of thetrack members comprises a rail.
 5. The apparatus according to claim 3wherein the upper surface of each track member comprises a rail and thelower surface of each track member comprises the base frame.
 6. Theapparatus according to claim 1 wherein there are provided roller memberssupported on each side of the trolley supported for movement along thetrack.
 7. The apparatus according to claim 6 wherein the roller membersare supported in pairs on axles mounted to the trolley.
 8. The apparatusaccording to claim 1 wherein the track is non-linear between the upperand lower ends thereof.
 9. The apparatus according to claim 8 whereinthe seat is pivotally supported on the trolley for pivotal motionrelative thereto.
 10. The apparatus according to claim 9 wherein thereis provided: a pivotal mounting mechanism for pivotally supporting theseat on the trolley for pivotal motion between the lower position wherethe seat is generally horizontal and the trolley is inclined along thetrack and a lifting position where the seat and trolley are bothinclined along the track and generally parallel to each other; and anabutment member mounted on the seat that abuts with the trolley toprevent the seat from pivoting passed the lifting position where theseat and trolley are generally parallel.
 11. The apparatus according toclaim 1 wherein the elongate driven member is an endless and flexiblemember.
 12. The apparatus according to claim 1 wherein the elongatedriven member is guided by idler members supported on the base frame.13. The apparatus according to claim 12 wherein one of the idler membersis floatingly supported on the base frame and biased in order tomaintain tension in the elongate driven member.
 14. The apparatusaccording to claim 1 wherein the elongate driven member comprises achain and the driver member comprises a sprocket for engaging the chain.15. The apparatus according to claim 1 wherein the driver devicecomprises a hand crank mechanism for rotating the drive member.
 16. Theapparatus according to claim 1 wherein the driver device comprises arotational member having a series of handles circumferentially spacedtherearound.
 17. The apparatus according to claim 16 wherein the handlescomprise openings in the rotational member.
 18. The apparatus accordingto claim 1 wherein the driver device is accessible by the personsupported in the seat.
 19. The apparatus according to claim 1 whereinthere is provided a locking mechanism for selectively preventing motionof the seat relative to the base frame.
 20. The apparatus according toclaim 19 wherein the locking mechanism is coupled between the driverdevice and the base frame.